This invention relates to the total synthesis of the .beta.-lactam antibiotic FR 1923 and related compounds. This antibiotic has been previously described in Belgian Pat. No. 830,934 and its isolation and characterization has been described by H. Aoki, et al., 15th Interscience Conference on Antimicrobial Agents and Chemotherapy, Abstract No. 97, September, 1975. The antibiotic has the following strucural formula. ##STR1##
Antibiotic FR 1923 has been obtained by culturing Nocardia uniformis var. Tsuyamanensis ATCC 21806 as described by U.S. Pat. No. 3,923,977 issued Dec. 2, 1975.
This invention relates to a process for the synthesis of antibiotic FR 1923. In particular, this invention relates to a chemical process for the preparation of the "nucleus" of antibiotic FR 1923. The nucleus is represented by the following structural formula: ##STR2##
This invention also relates to certain derivatives of FR 1923 and to the intermediates useful in the synthesis thereof.